#pragma once

namespace ys
{
	template<class T, class Container = vector<T>, class Compare = Less<T>>
	class priority_queue
	{
	public:
		priority_queue()
		{}
		template<class InputIteraor>
		priority_queue(InputIteraor first, InputIteraor last)
			:_con(first, last)
		{
			for (int i = (_con.size() - 2) / 2 ; i >= 0; i--)
			{
				adjust_down(i);
			}
		}
		bool empty() const
		{
			return _con.empty();
		}
		size_t size() const
		{
			return _con.size();
		}
		const T& top() const
		{
			return _con.front();
		}
		void push(const T& val)
		{
			_con.push_back(val);
			adjust_up(_con.size() - 1);
		}
		void pop()
		{
			swap(_con[0],_con[_con.size() - 1]);
			_con.pop_back();
			adjust_down(0);
		}
	private:
		void adjust_up(size_t child)
		{
			Compare com;
			size_t parent = (child - 1) / 2;
			while (child)
			{
				if (com(_con[parent], _con[child]))
				{
					swap(_con[child], _con[parent]);
					child = parent;
					parent = (child - 1) / 2;
				}
				else
				{
					break;
				}
			}
		}
		void adjust_down(size_t parent)
		{
			Compare com;
			size_t child = (parent * 2) + 1;
			while (child < _con.size())
			{
				if (child + 1 < _con.size() && com(_con[child], _con[child + 1]))
				{
					child++;
				}

				if (com(_con[parent], _con[child]))
				{
					swap(_con[child], _con[parent]);
					parent = child;
					child = (parent * 2) + 1;
				}
				else
				{
					break;
				}
			}
		}
	private:
		Container _con;
	};
}